Apparatus for the production of micro-organisms and for the fermentation of solutions



June 8, 1937. H. SCHOLLER ET AL 2,083,343

, APPARATUS FOR THE PRODUCTION OF MICRO-ORGANISMS AND FOR THE FERMENTATION OFSOLUTIONS Original Filed Sept. 24, 1934 2 SheetsSheet l NUTRIENT SOLUTIQN FERMENTED 13 f P! i 3 v SOLUTION AIR an al as YEAST SETTLING zouz 1s CIRCgSQWEING I SUSPENSION ZONE 1.

I :3 5 IDEPOSITEO YEAST Mkmwvfiks Patented June 8, 1937 aosas is APPARATUS ron THE PRODUCTION or MICRO-ORGANISMS AND FOR THE FEB,- MENTATION OF SOLUTIONS Heinrich Scholler; Sollm. near Munich, and Rudolf Eickemeycr, Munich, Germany Original application September .24, 1934 Serial No. 745.340. Divided and this application April 23, 1936, Serial'No. 76,082.

January Ill, 1933 l2-Claims. (01.195-142) mentation apparatus,

This application-is ,a division of our co-p ing application Serial No. 745,340, filed September 24, 1934.

This invention relates to. an

5 carrying out the accelerated production of .yeast and for the fermentation of solutions more particularly by the method disclosed in our copending application Serial No. 745,340. The method in question permits yeast to be obtained, and fermentation processes to be carried out, both continuously as well as intermittently. The method depends upon a combination of static and dynamic conditions, more particularly on the action of streaming conditions on suspensions and the deposition thereof and enables a considerable growth in the micro-organism and the separation of the same from the nutrient liquid to be carried out in a single operation with the substantially complete utilization of I all nutrient constituents. The method is also yeast mud has reached a certain layer thickness.

35 In order to carrythis principle into effect operations are carried out preferably with very high pitching quantities of yeast (high ye'ast concentration). Whereas in the usual processes the quantity of yeast present amounts to only" 'a few 40 per cent of the total nutrient substances and fermentation products present, the methodis advantageously carried out with quantities of yeast which are greater than the quantities of nutrient substances or fermentation products 45 present.

The yeast masses which deposit copiously on the inclined surfaces particularly when using high yeast concentrations and which fall down to-the bottom can be resuspended in the lower 50 part of the fermentation chamber, for example by means of suitable mechanical stirring devices or else by stirring with air or other gases. A.

part of the quantity of yeast, proportioned according to the yeast growth, is preferably gath- 55 ered or collected at the lower end of the ferapparatus for faces and to slide down;

In Germany either intermittently or continuously, by letting off through a sluice ar-j rangement, and if necessary thoroughly washed in the known manner, and may be worked'up to a dry product. 5

If the withdrawal of the yeast is effected'correspondinglto the yeast growth then the yeast concentration -in the fermentation chamber. can be kept constant in this way. The fermentation liquid flowing through the fermentation. 10 chamber leaves the top of the vessel after the nutrientsubstances contained in it are more or less consumed by the yeast and the yeastsuspended in it is wholly or. for the most part deposited. 15

In order .to secure a better effect vertical guid ing surfaces are preferably disposed in the middle of the fermentation apparatus, said surfaces being tubularly or prismatically arranged. The

following three zones aredistinguished within the fermentation vessel (of. Figure 4):

1. 'I'he suspension zone 50, which is sunrounded by the vertical guiding surfaces and in which the yeast is kept in' suspensionin a;

high concentration by the upwardly flowing;

.liquid:

2. The settling zone'52 which is disposed outside the suspe'nsion zone and in which .the velocity of flow is retarded and the direction of flow may even be reversed, so that the yeasthas an opportunity to settle on the inclined sur- 3, In between thesuspensionzone and the settling zone there may also be the circulation zone 5| in which'the fermentation liquid left moves from the -top to the bottom and again enters the suspension zon'e. 4 A The cross section of the suspension zone is preferablydimensioned so that the velocity of flow in, that zone is; automatically higher than 40 in the settling zone.

It advisable to supply a part of the microorganism leaving the-suspension zone, and may. be also a part of the yeast sliding downwardly l on the inclined surfaces. back into the'susp'ension zone again in order to be'able to maintain the desired high yeast concentration. This is this latter again, carries along with it the yeast 5 suspendedtherei'n and in certain cases drags it an excess of deposited. yeast which may be present and resuspends it. The additional upward motion of'the liquid within the suspension zone can be effected in various ways, for example bymeans of a propeller stirring mechanism which can simultaneously subdivide again and suspend the excess yeast mud, or, with avoidance of mechanical devices, by blowing in gases,

e. g. air, at the bottom of the suspension zone,

settling zone vertical or approximately vertical surfaces which again may be arranged in cir-' cular or prismatic fashion and have the object of compelling the liquid to reverse.

In aspecial form of carrying out the method the velocity of flow through the. apparatus and the yeast concentration are regulated so that part of the yeast suspended in more or less exhausted fermentation liquid leaves the fermentation vessel in order, for the purpose of eifecting further working. up or deposition, to be sub- Jected to a single or'manytimes repeated treatment in the same or-a similar manner.

Further, operations may also be can'ied out so I that no withdrawal of yeast takes place within the first fermentation apparatus and a quantity of yeast corresponding about to the growth of the yeast suspended in the issuing exhausted fermentation liquid leaves the apparatus, then to be separated off in a suitable manner, e. g. bymean of centrifuges. This manner of working, which avoids automatic separation of the yeast in the fermentation vessel or at least in the first fermentation vessel,

has, as compared with the usual yeast cultivation process, the further advantage that it operates continuously and moreover occupies only com The fermentation 'appaparatively small space. ratus according to the present invention may be connected both ,.in series as well as in parallel.

, The output capacity of the apparatus is, amongst other things, dependent on the size f the. in-

clined surfaces present. It has found preferable to. arrange several faces'one above the other, the downwardly sliding yeast, without beingstirred up or agitated, being guided by means of suitable funnel-shaped devices from one inclined surface to another down to the lowest inclined surface, where the whole of the downwardly sliding. yeast mud unites. The efficiency of an inclined surface is the greater the longer it is. It is preferable," therefore, so to adjust the streaming velocity over the individual inclined surfaces that the time of flow through just suffices to give the yeast opportunity to set le, in other words the rateof flow over the individual inclined surfaces is inversely proportional to the length of the inclined surfaces. 4

It is already known to promote the flocculation of micro-organisms, more particularly of yeast by adding alkali-and by production-of phosphate precipitates. It is also already known to bring scale-of the part I or Fig. 1;

with

about a similar action by means of-flock lactic acid bacteria (referred to in- German as "Flockenmilchsaurebakterien). These known expedi ents can be used when employing the apparatus of this invention, the corresponding agents being added either in the settling zone or operations being carried-out right from the start under conditions which are favourable for flocculating out yeast. Also.-micro-organisms which tend to produce flocculation may be employed in the process right from the commencement. i

The apparatus is put into operation in the known manner by means of pitching yeast which sary,"the leadfor the fermentation liquid can be used as well for introducing fresh seeding material if a proper pipe for this purpose, like the lead for the fermentation liquid, is not provided. It is known to be advantageous in many respects to subject the yeast, before it is supplied to its purpose of use, to a ripening process, inasmuch as the time the yeast remains in the lower part of the settling and circulation zones is insufficient for ripening, the ripening of the withdrawn yeast may take place in the known manner in a subsequently arranged vessel. Owing to the high yeast concentration the method is comparatively resistant to infection. Moreover, owing to its small space requirement and the continuous manner of working the method may be carried out in the apparatus in a known sterile manner. The high concentration of the yeast also enables the method to be used for working up nutrient solutions which contain fermentation poisons or substances which check fermentation, such as is the case with, for example, wood sugar liquors obtained by hydrolysis with dilute acid. The quantity of poisonous substances gaining access to the yeast cells is, in-consequence of the high yeast concentration, so small that it can be forthwith freed from poison by the cells.

' A further special advantage is that the so-called humin substances contained in the wood sugar liquor are prevented from settling since the fermentation liquid (wood sugar liquor with nutrient salts). flows through the apparatus in a comparatively short time. In .the case of small-apparatus the time of passage through the apparatus in which the fermentation takesplace is less than an hour, with large apparatus'a flow time of some few hours is to be reckoned with. v

Forms of the apparatus provided by the invention are described below with reference to the accompanying drawings together with a description of the manner in which the process is carried out with'the apparatus:

In the accompanying drawings: v Fig. 1 is an axial sectional elevation through a fermentation apparatus with simple treatment device; Fig: 2 is a detailed representation on a larger Fig. 3 is a sectional elevation through an improved formof fermentation apparatus (yeast production vessel), such as is particularly suitable for carrying out the procession a large scale.

Fig. 4 shows'a subdivision into zones of the fermentation vessel according to'Fig. 2.

' In Fig. 1, I is an inverted conical orpyramidal also Fig. which is closed underneath and has I this way continuously circulates there.

within the pipe 9 has tom an air or gas supply pipe .zwith a regulating cock 3 and a'fine aeration device 4, which is provided at the top with a filter plate 5 or the like.'

The supply pipe 6 is for the nutrient solution and has the regulating valve 1 and a funnel-shaped widened rtion 8 at the lower end thereof (see exit orifices at the top. Tubular or pipe members 9, In, ll, l2,'of the cylindrical or polygonal cross section, and open at the bottom and the top, dip

into the funnel-shaped vessel l at the top thereof;

the members with even reference numerals project somewhat out of the funnel-shaped vessel 1, whilst those with odd reference numerals arecut off at about the same level asuthe upper edge of the vessel or somewhat below: this level. An overflow channel l3, with one or several outlets I4, is provided. Closable disks, plates or the like, l5, are provided for lettingoff the yeast mud. The arrows indicate the most important directions of flow of the gases and liquids.

The manner of working the apparatus is as follows:

First consider the funnel-shaped vessel l to be full of liquid (nutrient solution). Fresh nutrient solution is then supplied downwardly through the pipe 6 up to the proximity of the filter plate 5 for the air supply. The air streams upwardly in fine bubbles and, in accordance with the injector or Mammut principle, causes the liquid with a large part of the yeast suspended therein to be guided upwardly again within .the pipe 9, as a result of which the yeast has opportunity to grow copiously in the fresh nutrient solution. When the liquid stream reaches thetop of the pipe 9 it tendsto spread radially outwards, but soon comes up against the projecting end of the pipe l and is there downwardly deflected in the annular space between 9 and Ill. The pipe l0 terminates at a distance from the side wall of the funnelshaped vessel such that if necessary a part of the now downwardlymoving suspension is led back by the injector action of the aeration device into the ascending current within thepipe 9 and in Another part of the suspension follows the direction of fiow which branches off at the lower end of the pipe l0 and is again brought to the'top in the annular 'space between pipe l0 and pipe II, where it spreads out in a radial direction again over the top end of the pipe II, is checked again by the pipe l2 as in the case of the pipe l0, flows down the annular space between pipe II and'pipe l2,- divides anew at the bottom of pipe [2, and so on.

At the first branching point of the direction of flow (at H in Figure 1) there is such a check according to the invention that the specifically heavier yeast parts, the settling tendency of which been" compensated for and overcome by the action of the ascending small bubbles of air, separate to a considerable extent from the flowing liquid, corresponding to the gravity, sink down onto the wall of the funnelshapedv vessel l and then under the action of gravity fall into the lowest part of the vessel, where they either collect around the air supply pipe and can be drawn off from time totime, or where they can be. continuously withdrawn -by means of suitably opened withdrawal valves or slides.

The circulation flow, which now forces the liquid upwardly again in the space between pipes 1 l0 and, 75

takes apart of the yeast with it again since there is tem 31, 32 and 33.

- faces 3|, 32 and 33 and on the no air stream here, which latter of course has alreadyleft the apparatus again at the top'of pipe 9, and since therate of flow is lower. The separation process is repeated at l8 insofar as the suspension still contains yeast, and

' the method may be conducted so that the liquid can now be led away practically without any loss in yeast. If the necessity should arise there is nothing to prevent still further pipes being-installed for the purpose of completing the yeast separation. According to the conditions of the case in certain circumstances even-fewer pipes may be provided than are shown in the accompanying drawings.

The angle of the side wall of the funnel-shaped vessel is determined on the basis of the angle of repose in such a way that, bearing in mind the surrounding liquid medium, a thicker collection of yeast on the wall of the vessel is avoided.

In order to regulate the flow both as regards its direction as well as its partial speed rotatable flaps l are provided which enable the cross section of the liquid between the lower end of the pipe in question and the outer wall of the funnelshaped vessel to be varied at suitable places.

These flaps serve more particularly to reduce the impact of the laterally deviated parts of the liquid on the yeast which slides down on the lateral wall. In this way any upsetting of the process is prevented, which was made apparent by the yeast deposited on the upper part of the side wall and provided with a system of at the bottom is used. The-manner in which the apparatus works is as follows:

The fermentation liquid is supplied through the pipe 22 and can be regulated by the valve 23. The fermentation liquid passes through the device 24, which is provided preferably at the top with small openings, into the suspension zone (Figure 4) within the prismatically disposed guiding surfaces 29. At the same time air is introduced into the air space 21 through the pipe 25 and regulating valve 26; the air is finely divided by the air subdividing device (filter 28). The ascending air at the same time sucks up fermentation liquid from below and any excess yeast mud which may be present. At the top edge of the guiding surfaces 23' the liquid enters the circulation zone 5! (of. Figure 4). A part of the liquid gets into the suspension space again at the lower end of the guiding surface 29 while another part flows into the inclined surface sys- The baffle is shown isadvisable but is not absolutely necessary. The yeast still present in the fermentation liquid deposits on the inclined surfaces 3|, 32 and 33 whilst the liquid freed from the yeast can be withdrawn through the run-off pipe 34. The rate of flow between the individual inclined surfaces may amongst other things also be regulated bycontrolling the' withdrawal (by means of valve 35) in which case a separate regulable withdrawal device may be arranged each two inclined surfaces.

The yeast which settles en the inclined sursurface 30 which inclined wall of between the trough 2| slides to the bottom and is collected by the funnel-shaped devices 38 in such a way that reagitation of the yeast is avoided.

The collecting yeast mud can be withdrawn by means of the pipe 31 and closure member 38.

In Figures 4 the three zones of the ferme'nta tion apparatus, the suspension zone 50, the set-. tling zone 52 and the circulation zone ii are indicated schematically. The individual zones II, M and 52 are distinguished by -shadlng.' The advantages of using the apparatus according to the invention for carrying out yeast cultivation andfermentation consist in the small space requirement and the high performance 'ofthe apparatus, in the automatic separation of the yeast, in the resistivity of the fermentation proc ess carried .out in the apparatus to infection.

and fermentation poisons, in the suitability of the apparatus for carrying out sterile fermentation and, inasmuch as aeration takes place, in an economical and efllcient aeration since in view of the high yeast concentration present in the suspension space only comparatively small quantities of air are used.

What we claim is:

1. An apparatus for fermenting solutions to produce products of fermentation and to produce micro-organisms such as yeast, comprising a vessel-having side walls diverging upwardly.

collecting means adjacent the bottom, of said a vessel having sidewalls diverging upwardly,

collecting means adjacent .the -'bottom of said vesselcooperating with said side walls to receive micro-organisms deposited "on said side walls, means to guide the flow of the fermentation liquid in a substantially upward and downward direction in said vessel, means to supply fermentation liquid-between said. guide means, means to. supply a gaseous fluid adjacent the supply means, means to remove the fermented liquid after it has completed its travel in said vessel, and means'to remove thecollected micro-organisms. A

3. An apparatus for fermenting solutions to produce products of fermentation and to produce micro-organisms such as yeast, comprising a vessel having side walls diverging upwardly, collecting means adjacent the "bottom of; said 'vessel cooperating with said sidewalls to re-' ceive fLmicro-organisms deposited on said side walls, means to supply a fermentation liquid to said vessel, means to guide the flow of the fermentation liquid in a substantiallyupward and downward direction insaid vessel, means cooperating with the side walls and at least some of the guide means for adjusting the rate at travel in said vvess l, and means which the deposited micro-organisms are delivered to the collecting means, means to remove the fermented'liquidafter it has completed its to remove the collected micro-organisms.

-4.'An apparatus for fermenting solutions-"to produce products of fermentation and to produce micro-organisms such yeast, comprising a vessel having side walls diverging upwardly, collecting means adjacent the bottom of said vessel cooperating with said side walls to receive microorganisms deposited on' said side walls, means to guide the flow of the fermentation liquid in a substantially upward and downward direction in said vessel, means to supply fermentation liquid between said guide means, means to supply a [gaseous fluid adjacent the supply means, meanscooperatingwith the side walls and at least some of the guide means for adjusting the rate at which the deposited micro-organisms are delivered to the collecting means, means to remove the fermerited liquid after it has completed its travel in said vessel, and means to remove the collected micro-organisms.

5. An apparatus for fermenting solutions to produce products of fermentation and to produce micro-organisms such as yeast, comprising a vee- -sel having side walls diverging upwardly. and inclined at an angle greater than the angle of repose. of the micro-organisms deposited thereon, collecting means adjacent the bottom of said vessel cooperating with said side wallsto receive microorganisms deposited on said side walls, means to divide the interior of said vessel into suspension.

circulation, and micro-organism settling zones,

said dividing means also constituting guide means to direct the flow of the fermentation liquid .in a substantiallyiupward and downward direction in said vessel, means to supply fermentation liquid' adjacent the suspension zone, means to remove the fermented liquid after it has completed its travel in said vessel, and, means to remove the collected micro-organisms.

6. An apparatus for fermenting solutions to produce products of fermentation and to produce micro-organisms such as yeast, comprising a vessel having side walls diverging upwardlyand inclined at an angle greater than the' angle of repose of the micro-organisms deposited thereon, collecting means adjacent the bottom of said vessel cooperating with said side walls to receive micro-organisms deposited on said side walls, means to divide the interior of said-vessel into suspension, circulatiomand micro-organism settllng zones, said dividing means also constit guide means to direct the flow of the fermenta tion liquid in a substantially upward and down-. ward direction in said vessel, means to supply fermentation liquid adjacent the suspension none, means to supply a gas'eousfluid adjacent the fermentation supply means, means to remove the fermented liquid after it has completed its in said vesseLand means to remove the collected micro-organisms.

7.,An apparatus forfermenting solutions to produce products of fermentation andto produce micro-organisms such as yeast. cmnprising a vessel having side walls diverging upwardly and inclined at an angle greater than the angle of repose of the micro-organisms deposited thereon, collecting means adjacent the bottom of said vessel cooperating with said'side walls to receive micro-organisms deposited on said side walls, means .to divide the interior. of said vesselinto suspension, circulation, and micro-organism set- I tIing zones; said dividing means also constituting l 70 tion liquid in a substantially upwardand downward direction in said vessel, means to supply guide means to direct the how of the fermenta- ,fermentaticn'liquid at the bottom of the suspension zone, means adjacent the top of said vessel to remove the fermented liquid after ,it has completed its travel in said vessel, and means to remove the collected micro-organisms from said collecting means.

8. An apparatus for fermenting solutions to,

produce products of. fermentation and to produce micro-organisms such as yeast, comprising a vessel having side walls diverging upwardly and inclined at an angle greater than the angle of repose of the micro-organisms deposited thereon, collecting means adjacent the bottom of said vessel cooperating with .said side walls to receive micro-organisms deposited on said side walls, means to divide the interior of said vessel into suspension, circulation, and micro-organism settling zones, said dividing means also constituting guide means to direct the flow of the fermentation liquid in asubstantially upward and downward direction in said vessel, means to supply fermentation liquid at the bottom of the suspension zone, means to supply a gaseous fluid at the bottom of the suspension zone, means adjacent the top of said vessel to remove the fermented liquid after it has completed its travel in said vessel, and means to remove the collected microorganisms from said collecting means.

9. An apparatus for fermenting solutions to produce products of fermentation-and to produce micro-organisms such as yeast, comprising a vessel having side walls diverging upwardly and inclined at an angle greater than the angle of repose of the micro-organisms deposited thereon, collecting means adjacent the .bottom of said vessel cooperating with said side walls to receive micro-organisms deposited on saidside walls, means to divide the interior of said vessel into concentric, suspension, circulation, and microorganism settling zones, said dividing means also constituting guide means to direct the flow of the fermentation liquid in a substantially upward and downward direction in said vessel, means to supply fermentation liquid at the bottom of the suspension zone, means to supply a gaseous fluid at the bottomof said suspension zone, means adjacent the top of said vessel to remove the fermented liquid after it has completed its travel in said vessel, and means to remove the collected micro-organisms from the collecting means.

10. apparatus for fermenting solutions to produce products of fermentation and to produce micro-organisms such as yeast, comprising -a vessel having side walls diverging upwardly and inclined at an angle greater than the angle of respose of the micro-organisms deposited thereon, collecting means adjacent the bottom of said vesselcooperating with said side walls to receive micro-organisms deposited on said side walls, means to divide the interior of said vessel into concentric, suspension, circulation, and microorganism settling zones, saiddigiding means also constituting guide means to direct the flow of the fermentation liquid in a substantially upward and downward direction in said vessel, means cooperating with said side walls to reduce the impact of the liquid with the micro-organisms deposited on said walls, means to supply fermentationliquid at the bottom' of the suspension zone, means to supply a gaseous fluid at the bottom of said suspension zone, means adjacent ti. top of said vessel to remove the fermentedliquidafter it has completed its travel in said vessel,' and means to remove the collected micro-organisms from the collecting means.

- 11. An apparatus for fermenting solutions to produce products of fermentation and to' produce micro-organisms such as yeast, comprising a vessel having side. walls diverging upwardly, means to divide the interior of said vessel-into suspension, circulation, and micro-organism settling zones, said dividing means also constituting guide means to direct the flow of the fermentation liquid in said vessel in a substantially upward and downward'direction, means to collect the deposited micro-organisms, means in the settling zone to receive the deposits of micro-organisms and deliver the same to the collecting means, means to supply fermentationliquid to the suspension zone, and means to remove the fermentation liquid after its travel in said vessel.

12. An apparatus for fermenting solutions toproduce products of fermentation and to produce micro-organisms such as yeast, comprising a vessel having side walls diverging upwardly, means to divide the interior of said vessel into suspension, circulation, and micro-organism settling zones, said dividing means also constituting guide means to direct the flow of the fermentation liquid in said vessel in a substantially upward and downward direction, means to collect the deposited micro-organisms, deposition surfaces disposed in the settling zones at an angle greater than the angle of repose of the depositing microorganisms, said surface being disposed to deliver the depositing micro-organisms to said collecting means, means to supply fermentation liquid at the bottom of the suspension zone, means to supply a gaseous fluid at the bottom of the suspension zone, and means to remove the fermentation liquid after its travel in said vessel;

HEINRICH SCHOILER. RUDOLF EICKEMEYER. 

